Fire alarm



Patented Nov. 18, 1947 UNITED STATES FIRE ALARM Louis L. Adolf, New York, N. Y.

Application April 23, 1946, Serial No. 664,204

2 Claims.

This invention relates to fire alarms, and more particularly to those of simple construction and of an inexpensive nature especially intended for use in homes, places of business, or in other locations, and by means of which an audible alarm will be sounded upon the outbreak of a fire and as soon as the re or excessive heat therefrom reaches the point of location of the alarm.

I am aware that prior to the present invention, attempts have been made to produce nre alarms of this nature, but such alarms have been generally those which required electricity as a source of power, thus utilizing the house wiring to convey the current to the alarm. Since many fires are caused by defective Wiring, or by short circuits therein and in which the wiring was at once rendered inoperative, it is clear that a fire alarm relying upon current conveyed by the house wiring, is undesirable. Hence the present invention relates to a device which is operated by its own built-in mechanical means, having no connection with the house current or other source of electricity.

The primary Object of the invention is to provide an alarm which is mechanically operated and which requires no external source of power. The result is that the alarm herein presented is self-contained and is truly portable and has no restrictions as to its placement Within a room for it may be placed Wherever desired, and in fact, several of the alarms might, if desired, be placed Within a single room. The device is one which is light in Weight, compact, and requires no installation other than merely setting it down upon a table, on the door or Wherever desired and it is ready to sound the alarm as soon as excessive heat reaches it.

More particularly, the invention contemplates a spring-operated audible signal means, such as a bell, buzzer or the like, and a means for normally restraining the spring motor from operation, the restraining means includinga part or parts affected by abnormal or excessive heat, and caused to be rendered ineffective to restrain operation of the alarm when reached by the excessive heat.

The above stated results may be obtained by various constructions, an illustrative one being hereinafter set forth and more particularly pointed out in the claims appended hereto.'

In the accompanying drawing, forming a part hereof, Fig. 1 is a top plan view of the improved alarm, with parts shown in section and the cover or casing removed to clearly disclose construction; Fig. 2 is a front view of the alarm apparatus,

PATENT OFFICE with the cover and base shown in section; Fig. 3 is an end View of the device, looking at the right end of the same, with the bell omitted from this view to avoid congestion in the drawing, and the cover and base shown in section, and Fig. 4 is a top plan view of a part of the cover, showing the locking means for holding the spring motor in an unwound position,

With reference to the drawing, I indicates the base plate of the device, the same being preferably composed of a metal stamping, or it may be made of any other material not readily affected by heat. Secured on the base I is a bearing 2 which co-operates with a similar bearing 3 carried by the cover member 38 to rotatively support a vertical shaft 4. The vertical shaft 4 constitutes the motor shaft, and one end of the spiral spring motor 'I is secured to the shaft 4, the opposite end 8 of the spring motor being attached to a 20 post 9 rising from the base plate I.

The shaft 4 extends through an aperture in the cover 38 and on the outside of the cover, the shaft 4 is provided with a winding key 2| by which the shaft 4 is manually rotated to wind up the motor I in the conventional manner of spring motors of this general kind. Secured on the shaft 4 is a ratchet wheel 6, which is normally engaged by a pawl 22, said pawl being pivoted at one end on a post 23 rising from the plate or base I. The opposite end or nose of the pawl normally engages the ratchet wheel 6 to thereby hold the spring motor from unwinding The pawl 22 is normally held in engagement with the ratchet wheel 6 by means of a coil spring 28, which has one end secured at 21 to the pawl 22 and has its Vother end secured at 29 to a link 30 fixed to an upstanding post 3I. At its opposite end, the pawl 22 is provided with a lug 24 to which one end of a coil spring 25 is secured, the opposite end of said spring 25 being attached to a post 26 rising from the base plate I.

It is to be noted that the spring 28 is considerably stronger than the spring 25, with the result that the greater pull of the spring 28 overcomes that of the spring 25 and thus the pawl 22 is normally held in engagement with the ratchet wheel E, and the spring motor 'I is thereby held from unwinding, with the gear 5 remaining at rest.

The link 3, and possibly the post SI, or both of these elements if desired, are composed of a material very sensitive to excess or abnormal heat, and to such an extent that in the presence of relatively low temperature, these parts or either of them, will first distort and then disintegrate, or even fall apart almost immediately upon the imposition of excess heat upon them, the action of the parts being dependent upon their nature. The material employed for these parts, or either of them, should be one which quickly disintegrates under heat and even without actual contact of the flame so that when a re occurs to create the heat required to cause the collapse or disintegration of these parts and they do so, the lighter spring 25 will at once become effective to overcome the pull of. the heavier spring 28, so that the pawl 22 will then be pulled out of engagement with the teeth of the ratchet wheel 6, and the ratchet wheel, and resultantly the gear 5 carried thereby, will be at once freed and caused to rotate under the impulse of the spring motor 'I.

In mesh with the teeth of the gear 5 is a pinion I0, rotatively mounted on a vertical stud shaft I I iixed in a boss I2, said pinion carrying or being attached to a cam I2a which is operative, upon rotation of the pinion I0, to cause oscillation of a clapper arm I3, pivoted at I3a to a post rising from the base I'. On one end of. the clapper arm I3is secured the head I4 which is normally pulled toward and against a bell I5, mounted on a post I8 secured in the boss I'I on the base platev I. A spring I8 hasl one end attached to a pin 20 extending downwardly from the clapper arm I3, and its other end attached to a lug I9 on the boss I?. The structure is such that as the cam I2aI is rotated, it will swing the headed end of the clapper arm I3 away from the bell and the spring IBwill return it and cause it to strike against the bell'.

From` the foregoing, the operation of the improved alarm will be apparent. When the device is not' in use, tension on the spring motor 'I may be removed by manually releasing the pawl 22 from its engagement with the ratchet' wheel 6. For this` purpose, it will be noted that the pawl 22 is provided with a. release lever 32 which rises from the top of they pawl and projects through a guide slot inthe top of the cover 38. The release lever is provided with a top section 34, pivotally secured at 33, toy a lower part 32, the top section 34 having a knob or ball 35 by which it may be engaged by the fingers.

The slot 3'Iv is provided at one end with an oiset exten-sion and when it is desired to release the pawl to allow the -spring motor 1 to run down, the knob 3l is manually pushed toward the end of the slot 31. and when it reaches this end of the slot, the top portion of the lever 34 is moved sidewisely to swingv it into the oset part of the slot, thus holding the lever 32 against return movement and maintaining the pawl away from the ratchet wheel 6 and allowing the spring motor to run down. When the spring motor has fully unwound, the lever 3'2 may be restored to it-s normal position inI Fig. fl and the alarm may be placed away until it is to be used. This release means isv also useful t'o test the bell-operating mechanism at any time.

Toy place the alarm in condition for use, it is merely necessary to wind the key 2| until the spring motor l is fully wound and then set the device down at any desired location in a room. Should a re break out, or any excessive heat be created, the heat-sensitive elements 3Ilor 3|' or either of them, will distort or disintegrate; spring 2.8 will' then be either separated from its anchorage to the link 30', or else link 30 will elongate to such an extent as to allow spring 25 to pull the pawl 22 from its engagement with the ratchet wheel 6. When this occurs, shaft 4 will at once be set in rotation by the spring motor 1; gear 5 will rotate the pinion Ill and the cam I 2a will rapidly vibrate the clapper arm I3 to vigorously ring the bell I5 and awaken sleepers.

Through the arrangement described, it will be clear that a means is provided by which an alarm can be sounded as soon as heat aiects the means for holding the audible signal device against operation. Such heat-sensitive means may be made in various forms according to the heat-sensitivity required. The heat-sensitive element can be made in the form of a strong but slender thread which will be readily ruptured at reasonably low temperature. In the embodiment shown, all of the parts of the device are housed in a suitable cover or casing, such as is shown at 38. In practice it may be found desirable to enclose only some of the parts, namely, the bell-operating mechanism, while the heat-sensitive elements might be left exposed to thereby more readily subject the same to the heat created when a re arises.

While I have herein shown the bell-operating device of a certain construction, it will be clear that various other types of bells and actuating means therefor might be employed in conjunction with the novel heat-sensitive means disclosed, for setting the bell-ringing means in operation. Hence, while having described one embodiment of the invention, it is obvious that the same is not to be restricted thereto, but is broad enough to Acover all structures coming within the scope of the annexed claims.

What I claim is:

1. In a lire alarm, a base, an audible signal including a bell on said base, a spring motor and a bell-clapper operated by said motor, a ratchet wheel forming a part of the spring motor, a pawl in engagement with said ratchet wheel, meansfor holding the pawl normally in engagement with the ratchet wheel consisting of a spring having one end connected to the pawl and its other end attached to a heat-destructible element, said heat-destructible element being attached to the base, a second spring operative with relation to the pawl to cause the pawl to be disengaged from the ratchet wheel upon disintegration of the heatdestructible element upon the imposition of abnormal heat upon said element, and manually controlled means by which the pawl may be disengaged from the ratchet wheel and' caused to be maintained in such disengaged position until released by operation of said manually-controlled means.

2. In a re alarm as provided for iny claim l, wherein the manually-controlled means consists of a projecting handle portion on the pawl, a slot in which said handle portion is manually movable, said slot having an olset end portion into which the handle is adapted to be extended to thereby cause the pawl to be held in a position of disengagement from the ratchet wheel against the pull of the nrst spring.

LOUIS L. ADOLF.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 298,981 Judson May 20, 1884 1,509,110 Potter Sept, 23, 1924 2,085,860 Lambert July 6, 1937 

